Apparatus for testing friction material



May 25, 1948. D. E. DASHER I 2,441,993

APPARATUS FOR TESTING FRICTION MATERIAL Filed Dec. 5, 1945 .E- h I E15:11:. EL

' INVENTOR.

Do/v E. DASHER UNITED STATES PATENT OFFICE APPARATUS FOR TESTINGFRICTION MATERIAL Don E. Dasher, Detroit, Mich assignor to BendixAviation Corporation, Detroit, Mich., a corporation of DelawareApplication December 5, 1945, Serial No. 633,015

3 Claims.- (or. 73-7) This invention relates to testing apparatus, and

particularly to apparatus for, testing the wearing and endurancequalities of friction materials.

Brake linings, clutch facings, and similar ar- 2 ance and secured in thedisc 24 with semi-spherical members 34' interposed between the discs, soas to provide for slight rocking movement of the disc 30.

ticles are tested in a variety of ways, but all test A spindle 36suitably secured in the hub 26 of methods heretofore used are less thanentirely the disc 24 has an enlarged portion 38 calibrated satisfactory.Either they involve excessively exin pounds as indicated at 40 and inthe upper pensive or complicated equipment and methods, end of theenlarged portion is a diametral pin 42. or they are not suflicientlyslmulatlve of actual A sleeve 44 fitted for reciprocation on theenconditions encountered in practical use. larged portion 38 has one endclosed as by a head An object of the present'invention is to pro- 46supporting a concentrically disposed spindle vide an inexpensive andsimple apparatus for 48.

carrying out a highly informative testing tech- The sleeve 44 is slottedas at 50 for the recepnique. tion of the pin 42 and a spring 52 ispositioned Other objects and features of this invention in the sleevebetween the enlarged portion 38 of will appear hereinafter, or willsuggest themthe spindle 36 and the head 46 of the sleeve 44. selves tothose skilled in the art in the following Pressure applied through thespindle 48 results specification, reference being made also to the inmovement of the sleeve on the enlarged portion accompanying drawingillustrating one embodi- 38 of the spindle 36 against the resistance ofthe ment of the invention. It is'to be understood, of spring 52 and asthe lower end of the sleeve course, that other embodiments are alsoemmoves over the calibrations 40 a visual indication braced in theappended claims. is had of the pounds of pressure applied, and this Inthe drawing: pressure is transmitted through the rotatable Fig. 1 is ageneral assembly view; disc 24 to the parts under test against the plateFig. 2 is an enlarged fragmentary view in seci6. tion of a portion ofthe complete assembly; and. The driving assembly includes an electricmo- Fig. 3 is a bottom plan view of one of the segtor 54' having itsarmature shaft enclosed in a ments used for test purposes. housing 56and suitably connected to a recipro- Referring to the drawings for morespecific cable extension 58 carrying a spindle 60 having details of theinvention Ill represents a base havthereon a chuck 62 for the receptionof the spining thereon legs l2 supporting a plate 14 adapted dle 48, anda bracket 64 on the housing 56 has to be electrically or otherwiseheated, and supivoted thereto a hand lever 66 connected as by perimposedon the-plate i4 is a smooth surfaced a pin 68 to the reciprocableextension 58 of the steel cooling plate 16 havingpassages l8 extendedarmature shaft. therethrough. By applying force to the hand lever 66con- Manifolds 20 and 22' suitably secured to the trolled pressure maybe transmittedthrough the ends of the plate It serve to connect thepasarmature shaft extension 58, the spindle 60 carsages iii to oneanother and also to connect the ried thereby, and the chuck 62 to thespindle 48, passages to a suitable water supply and disthence throughsleeve it, the spring 52 and charge, to the end that water may becirculated spindle 36 to the disc 24 carrying the parts under throughthe plate l6 so as to decrease heat gentest. erated in the plate M. Asuitable source of current 10 supplies the A disc 25 having a hub 26 hasmounted thereon operating pow-er to the motor 56, and a meter 12 blocksor segments 28 of friction material to be is inserted in the conductiveleads from the tested. The blocks or segments are of such a source ofcurrent 70 to the motor 56 in order to character as are commonlyemployed for applimeasure the current consumption under varying Cationto e rotating parts of wheel assemblies conditions throughout theduration of the test 011 c a t landing gear to D Ce a braking to whichthe segments 28 are being subjected. action as the craft makesengagement with and This current consumption indication constitutesrollsalong the ground as upon landing of the one means of determiningthe physical charac aircraft. teristics of the parts under test, thatis, the wear- As shown, the segments 28 of friction material ing of thesegments and endurance qualities are ported on a disc 30 as by screws orother thereof. If the consumption of current is high it suitable means32 passed through openings in indicates that the material under test hasa high the friction material and disc 30 with small clearm m; offriction, and conversely if the consumption of current is low itindicates that material has a'low coefficient of friction.

In conducting a test of the frictional material constituting thesegments 28 heat is applied through the plate I, in any desired amount,preferably corresponding to the amount of heat which would be generatedin actual use of the segments 28 in whatever application it may be madethereof. In instances where the amount blies to which the segments areapplied, and the wearing quality of the segments is determined bycomparative measurements of the thickness of the segments before andafter the test.

While this invention has been described in connection with certainspecific embodiments, the principle involved is susceptible of numerousother applications that will readily occur to persons skilled in theart. The invention is, therefore, to be limited only as indicated by thescope of the appended claims.

Having thus described the various features of the invention, what Iclaim as new and desire to secure by Letters Patent is:

1. An apparatus for testing the physical characteristics of frictionmaterial comprising a stationary member having a smooth surface, meansfor heating the member, means for cooling the 35 member, a rotatablesupport for the material under test associated with the member, meansfor applying pressure through the rotatable support for pressing thematerial under test against the smooth surface of the member duringrotation thereof, electrical means for driving the rotatable support,and a meter for measuring the electric current consumed by the electricdriving means.

2. An apparatus for testing the physical characteristics of frictionmaterial comprising a stationary member having a smooth surface, meansfor heating the stationary member, means for cooling the stationarymember, a rotatable member for cooperation with the stationary member,means on the rotatable member for supporting the material under test inengagement with the stationary member, means for applying pressure onthe rotatable member, electrically driven means for driving therotatable member and a meter for measuring the current consumed-by theelectrically driven means when driving the rotatable member.

3. An apparatus for testing the physical characteristics of frictionmaterial comprising a stationary member having a smooth engagingsurface, means for controlling the temperature of the engaging surface,a rotatable member for cooperation with the stationary member includingautomatically adjustable means for supporting the material under test ina uniform engagement with the engaging surface, manually operatedcalibrated means for controlling contact pressures between the frictionmaterial and the engaging surface, electrically driven means for drivingthe rotatable member, and means for indicating the power consumption ofthe driving means.

DON E. DASHER.

REFERENCES orrED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

